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RBL · Posted: Fri Apr 18, 2008 5:48 pm Post subject: new engine build

I'm building another 1.7 8valve carburetored engine from a '93 injected 8v. However, being fuel injected, the hole for the dizzy and fuel pump are blocked. I had hoped these would just be plugs but they haven't been machined so I need to swop the rear engine casing (flywheel housing) for another one.

Does anyone have one or a scrap engine? (Is this the only problem I'm going to encounter? I suppose I'll have to think about the dizzy worm drive and fuel pump internal mechanics)

Thanks
Rich
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Porsche 550 spyder replica with Alfa Sprint 1.7 engine

Admin · Posted: Fri Apr 18, 2008 9:03 pm Post subject:

Hi

It is only the very late 8V that don't have a dizzy. Fuel pump might be an issue but might be easier to replace with a low pressure electric one.

To be honest I would be more inclined to use the crankshaft position sensor and wire up a custom ignition system rather than modify it to use a distributor.

All the best

Keith
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rsfruitbat · Posted: Sat Apr 19, 2008 8:18 am Post subject:

If you get stuck I have got rear castings, probably an old pump and I also have a pair of Facet silver top pumps if you are interested. PM me if you are. Based on what I found with my 16V engine programmable ingnition is way to goso agree with Admin. I would be tempted to stick with fuel injection aswell

rsfruitbat

RBL · Posted: Sat Apr 19, 2008 9:44 am Post subject:

Thanks guys, I'd thought of that and for a number of reasons I want to stick with carbs and distributor. I'm stripping it back to the block and re-building it with a slight compression increase so the rear engine casing is coming off anyway. Once done, when I want to, it's just a simple swop with my current engine with with a change over of carbs and other bits.

rsfruitbat - Thanks for the offer of the casting, I'll PM you.

Can anyone answer my last question? I can't remember from when I built the first engine, but does the crankshaft differ? ie does the crankshaft drive the distibutor and pump?
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Porsche 550 spyder replica with Alfa Sprint 1.7 engine

Admin · Posted: Sat Apr 19, 2008 12:07 pm Post subject:

Hi

From memory the dizzy and oil pump are on one shaft driven off the same gear on the crank.

All the best

Keith
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I owe, I owe, its off to work we go.
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ZeNiTh-PbArM · Posted: Sun Apr 20, 2008 9:17 am Post subject:

Hi,

yes the crank has a worm gear pre-installed to drive oil pump.
your oil pump shaft has the required cam to drive fuel pump
also the notch to drive ignition dizzy

ignition dizzy hole in rear casing is closed by a plug, easy to remove.
fuel pump is another matter as it will need machining of the face to ensure proper distance from the cam, which affects fuel pressure drastically.
Early Suds could be fitted with 3 different pump rods to compensate inaccurate machining of the casting

regards,
zp

RBL · Posted: Sun Apr 20, 2008 10:36 am Post subject:

Thanks ZP, very helpful. I might remove the dizzy plug and machine and tap the fuel pump 'manifold'.

I want to keep things simple and the standard mechanical fuel pump works perfectly well - unless someone can give a good reason for changing to electric pump? It's just an evening project to build a smooth, balanced torquey engine.
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Porsche 550 spyder replica with Alfa Sprint 1.7 engine